Final Report Further analysis of decontaminated recycled ... analysis of decon rPP.pdf · Further analysis of decontaminated recycled polypropylene (rPP) 1 Executive summary Introduction

Final Report

Further analysis of

decontaminated recycled

polypropylene (rPP)

A summary report that investigates the significance of residues of printing inks and labels on the food grade status of recycled Polypropylene from post-consumer food packaging.

Project code: IMT003-105 Research date: August to December 2012 Date: July 2013

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Document reference: [e.g. WRAP, 2006, Report Name (WRAP Project TYR009-19. Report prepared by…..Banbury, WRAP]

Written by: Edward Kosior

Front cover photography: [coloured PP flakes]

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Further analysis of decontaminated recycled polypropylene (rPP) 1

Executive summary

Introduction Closed loop recycling of food packaging waste is already possible for PET (soft drinks bottles) as well as HDPE (milk bottles) and PP is the next most prevalent polymer in the household packaging waste stream. WRAP has therefore undertaken a programme of work to identify a commercially viable process to recycle PP packaging waste, (widely used to make rigid plastic packaging such as pots, tubs and trays) back into a food grade recycled PP (rPP). This will enable brands, retailers and packaging manufacturers to close the loop and use rPP to manufacture new food packaging with a reduced carbon impact. The recycling rate for rigid PP packaging will need to grow over the coming years to meet the UK packaging waste recycling targets (57% by 2017 for obligated companies, to achieve an overall recycling rate of 42%). End markets will also need to grow and develop to keep pace with the additional material being recycled. With packaging accounting for over 40% of demand for PP, and most of it for food applications, there is a significant opportunity to use rPP back into food packaging if the technical and commercial barriers can be overcome to produce a food grade material that meets EU regulations. This project builds on the previous phases in the development of a viable food grade PP recycling process. These are presented in the WRAP project reports; “Scoping study into food grade polypropylene recycling” (2010), “Development of a Food Grade Recycling Process for Post Consumer Polypropylene” (2011) and “Food grade decontamination trials of household PP waste” (2012). Work to date shows that by using a combination of decontamination systems as part of a recycling process for post consumer polypropylene (PP) food packaging, the two grades produced (clear and coloured rPP) are suitable for a wide range of food contact applications for aqueous, acidic and many fatty foods under severe heating conditions and prolonged storage at room, chilled and frozen temperatures. A noticeable characteristic of the PP packaging used in the previous work was that the majority of the packaging had been printed or utilised “in-mould labels” (IMLs) as a form of branding and decoration on the outside of the packaging where they are not required to be suitable for direct food contact. This raised questions relating to trace levels of ink residues remaining in the post consumer rPP that had been decontaminated by the process previously tested and if they had an impact on meeting all the EU regulations relating to the level of these specific substances and the conformance with food contact regulations. This report addresses that question. Objectives of this study The specific objective of this work was to confirm whether the recycled PP (rPP) resins made by a new recycling process from post consumer food packaging decorated with “in-mould labels” and direct printing inks meet the EU regulations for food contact. Project methodology The key stages in this project were to:

1. Review the existing test results and other information sources to determine what specific compounds are most likely to be present and also to be of concern as additives in packaging used in direct food contact.


2. Detect any traces of residual chemicals that may have been present at very low levels in the previous studies but not quantified in the two 100% rPP resin samples used in the last project, i.e. coloured and clear rPP.

3. Identify the types of molecules present, on a quantitative basis using GC/MS and LC/MS.

4. Assess the status and allowable limits for direct food contact for all identified substances with reference to the EFSA (European Food Safety Authority) and USFDA (The United States Food and Drug Administration) regulations as well as scientific literature.

5. Predict the migration of any residual chemicals detected at the measured concentrations into food under worst-case conditions of food type and temperature together with chilled and ambient storage.

6. Evaluate the residues that have unknown toxicological properties using “Threshold of Toxicological Concern” (TTC) which evaluates the substances based on the chemical structural classes and their related carcinogenic and or toxic potential.

7. Confirm whether the EFSA and USFDA regulations have been met by this material for direct food contact. The results and conclusions of these investigations were reviewed by a leading chemical law attorney (Steptoe and Johnson LLC) who were asked to review any classifications of residual substances and to validate their toxicity and human exposure levels as well as to review the conclusions and recommendations on the TTC approach.

Identification of traces of printing residues in post consumer PP packaging The two rPP resins were extracted and then analysed. The substances identified qualitatively in the two resins were very similar however, for the clear rPP more oligomers were extracted. The analysis identified twelve compounds used in UV cured inks and one substance (DEGBA) used in ink formulations. Toxtree v2.5.1 was used to understand their potential toxicity and to be able to define the safe exposure limits. The thirteen residues were also categorized by the Swiss Ordinance Annex 6. The Annex has evaluated the migration limits for many of the substances and also defined a lower limit of detection of 0.01 mg/kg or 10 ppb for substances that should not be used with food (Swiss Part B list). The Swiss Ordinance is used as a point of reference since there are no EU regulations specifically covering a positive list and the Swiss Ordinance has recently been used by the German Federal Institute for Risk Assessment (BfR) as the basis for their draft Ordinance. A quantitative analysis of each substance by GC/MS equipment to levels close to the limit of detection determined the average concentration of each substance was then used in a migration-modelling program to predict levels of migration into food using worst-case scenarios with olive oil as a food simulant at temperatures up to 60°C. The specific migration limit (SML) applied to each substance was also evaluated. The SML defines a safe limit set by the EU for specific substances that may have toxicity issues at higher levels. The Swiss Ordinance Part B sets the migration limit for substances on the list at 0.01 mg/kg or 10 ppb. Both clear and coloured resins had similar concentrations for nearly all of the residues and that most of the concentrations were below 20 ppb indicating that the analysis would be technically challenging. The results of the migration modelling for 20°C, 40°C and 60°C showed that in all thirteen substances the quantity predicted to migrate to food was less than the specific migration


limit (SML) for that substance. The only result that was close to the limit was for the most abundant substance, 4-phenylbenzophenone, which was less than the SML by 20% at 8 ppb compared to the limit of 10 ppb. All of the estimated migration values were less than the limits specified by the Swiss Ordinance regulations and therefore the two resins were in compliance with the Swiss Ordinance and the recommendations of the “suitability list” of the European Printing Industries Association (EuPIA) for low-migration UV printing inks. Conclusions based on the migration data on food safety of the rPP resins On this basis, the two recycled PP resins represent a negligible risk based on the specific migration limits recommended by the Swiss Ordinance and could be used in direct food contact applications with the confidence that the residues from ink and labels remaining in the rPP would not migrate into food at levels exceeding those recommended. Regulatory position for printing residues in USA and Europe The legal firm of Steptoe and Johnson carried out a review of the data and examined the technical results in order to determine whether the decontaminated rPP resins comply with EU and US regulations and are suitable for direct food contact on the basis of the presence of the identified ink residues. The highlights of their key observations and conclusions are presented below. However, please note that this summary should not be relied upon in isolation. Readers are specifically directed to read the full review (within Appendix 3). They determined that the two resins complied with EU Framework regulation 1935 /2004 Article 3, which ensures that packaging does not endanger health and does not “unacceptably change” the composition and taste of food, In addition the rPP resins complied with EU Regulation 10/2011 that allows for the demonstration of the safety of non-intentionally added substances (NIAS) that are not on the EU list of positive materials by migration testing. Similarly they stated that the resins would comply with the USFDA regulation 21 CFR 174.5 “Requirements for recycled plastics used in food contact applications” since it could be demonstrated that the residues would not migrate at levels that would create dietary intakes that would exceed those recommended and therefore represented negligible risk. In reaching this position Steptoe and Johnson thoroughly reviewed the analytical procedure and made conservative adjustments to the migration results by assuming the actual migration was double of that predicted by Smithers-Pira, who undertook the quantitative analysis. It was concluded that “the potential risk from migration of these substances from food contact polypropylene can be considered negligible and the two recycled polypropylene batches can be considered of suitable purity for their intended use under 21 CFR 174.5, with respect to these thirteen migrants”. Steptoe and Johnson concluded that the two batches of rPP can be considered of suitable purity for use as food packaging under the EU regulations and USFDA regulations. Conclusions The investigations conducted on the two grades of clear and coloured rPP resins produced by the specific recycling process described in UK patent application (No. 1103495) related to this project have shown that:


1. Most of the inks present on PP packaging as direct print and IMLs have been removed during the washing process through the application of the abrasion and chemicals used in the washing process;

2. Thirteen residues from the printing inks and IMLs have been detected in both resins; 3. The residues are present in very low concentrations and are not likely to migrate to

food, even under extreme temperature and food type, in concentrations that will endanger human health;

4. The two resins are compliant for food use according to the regulations used in the EU as well as USA;

5. Using the TTC approach provides useful guidelines for the classification of substances that have not been fully studied with regard to their specific toxicology;

6. These results confirm that the rPP with in-mould labels and direct printing inks that has been decontaminated with the process described in the specific recycling process (UK patent application No. 1103495), is suitable for direct food contact use in conditions representing storage for 10 days at 60°C covering ambient storage over 6 months as well as chilled and frozen storage. These comments are specifically directed to the migration of substances used in in-mould labels and printing inks and should be considered along with earlier recommendations relating to the limits on food types and storage conditions for the two types of rPP which showed (amongst other acceptable conditions) that the rPP resins could be used with many fatty foods for 10 days at 40°C as well as other specific food types (aqueous and acidic) and other temperature conditions up to 121°C;

7. The results should provide confidence to the packaging and recycling industry to take on the development using the methodology presented here to develop and commercialise a food grade recycling process for post consumer PP packaging. It has provided a methodology to continually measure/test/monitor the presence of substances of concern that could be used throughout the commercialisation/development process; and

8. The commercialisation of the specific recycling process or others of similar or better decontamination efficiency can proceed with the knowledge that there are negligible risks of contamination from the presence of printed labels and direct printing. The remaining technical issue will be the need to develop techniques that can separate prior-food-use packaging from non-food use packaging.

Recommendations It would be helpful if food safety and industry bodies conducted research into printing systems and their ingredients in different parts of UK and Europe to understand how the printing ink residues in post consumer PP packaging might vary from to those measured in this study based on UK sourced PP packaging.

One residue (4-phenylbenzophenone) extracted from the rPP was measured at levels that were safe but significantly higher than any of the other ink residues. It would be useful if food safety and industry bodies investigated why this component was present in relatively large concentrations to understand any potential impacts on exceeding migration limits. The printing industry is also changing its formulations as it is challenged by new regulations for worker health and safety and it would be appropriate for these changes to be monitored so that any implications of eliminating some components and introducing new substances are understood. This can be readily achieved by close liaison between food safety bodies and an industry association such as European Printing Industry Association (EUPIA) or by setting manufacturing specifications.


Contents 1.0 Introduction and scope of the project .......................................................... 8 2.0 Project Methodology .................................................................................. 10 3.0 Identification of traces of printing residues in post consumer PP packaging 11

3.1 Identification of contaminants from previous use of printing inks and in-mould labels 11 3.2 Threshold of Toxicological Concern (TTC) .................................................. 11 3.3 TTC Classification of ink residues in rPP ..................................................... 13 3.4 Quantitative analysis of contaminants in rPP resins ..................................... 14 3.5 Migration simulation ................................................................................. 17 3.6 Conclusions based on the migration data on food safety of the rPP resins ..... 18

4.0 Review of compliance with US FDA and EFSA regulations ......................... 19 4.1 Legal attorney review of the analytical results ............................................ 19

5.0 Conclusions ................................................................................................ 21 6.0 Recommendations ...................................................................................... 22 7.0 Bibliography ............................................................................................... 23 Appendix 1. Analysis of residues in rPP (Smithers-PIRA) .................................... 24 Appendix 2. Quantitative analysis of contaminants in rPP from printing inks (Smithers-Pira) .................................................................................................... 32 Appendix 3. Report on rPP for direct food contact – Steptoe and Johnson LLP ... 47

Figures Figure 1: Clear and coloured PP flake prior to processing ................................................. 9 Figure 2: Clear and coloured PP flakes with residual print prior to processing ..................... 9 Figure 3: Concentration and migration of residues in clear PP. ........................................ 17 Figure 4: Concentration and migration of ink residues in coloured rPP ............................. 17

Tables Table 1: Substances identified in rPP compounds by solvent extraction ........................... 11 Table 2: Summary of TTC categories and exposure levels by person, body weight and in food ............................................................................................................................ 13 Table 3: Classification of residues in rPP resins by Swiss Regulation and Cramer Class ...... 13 Table 4: Average concentration of residues in rPP and migration into food ....................... 15 Table 5: Limit of detection for each substance ............................................................... 16 Table 6: Migration and Estimated Dietary Intake (EDI) results for clear (Sample 1) and (Sample 2) coloured rPP (Steptoe and Johnson) ............................................................. 20


Glossary of Terms

µg/p/d Micro grams per person per day ADI Acceptable Daily Intake Benzophenone UV absorber used to initiate UV curing of inks (CAS No.119-61-9) CAS No. The CAS Number of a compound is a unique way to identify a chemical

over its name and can be looked up on the Chemical Abstracts Service (CAS) database

Cramer Class Classification of the potential toxicity of substances based on the structural similarity to substances of known toxicity. There are three classes; I, II and III with each one increasing in potential toxicity

EDI Estimated Dietary Intake EFSA – European Food Safety Authority EuPIA European Printing Industry Association Food Contact Polymer or Packaging -

That which has been used in contact with food or has been tested and approved for use in contact with foods in compliance with the requirements of EU Regulation 10/2011.

genotoxicity Deleterious action on a cell's genetic material affecting its integrity GC/MS Technique of analysis using gas chromatography and Mass spectroscopy

that is widely used for volatile substances IML In mould label LOD Limit Of Detection of the analytical equipment in detecting substances LC/MS Technique of analysis using liquid chromatography and Mass

spectroscopy that is widely used for non-volatile substances Migratest Lite Model

Modelling software that estimates the migration of substances under various conditions

Mutagenicity Tendency of a substance to increase (Swiss FDHA, 2005) the frequency of mutation in an organism

NIAS Non-intentionally added substance Oligomers Low molecular weight sections of the polymer potentially from

degradation Padmate O UV absorber used to initiate UV curing of inks. Chemical name is (2-

ethylhexyl 4-(dimethylamino)benzoate) CAS No. 21245-02-3 Phosphine oxides Catalysts for the UV curing of printing inks PCR – Post consumer recyclate PP – Polypropylene ppm - Parts per million ppb - Parts per billion Residence time - Time spent under specific processing or decontaminating conditions rPP - Recycled polypropylene SML Specific migration Limit used to limit the migration of substances that

might have toxic effects at higher migration levels Toxtree Software that uses chemical structural properties to classify the

potential toxicity of substances that have not been evaluated with actual toxicity studies

TTC Threshold of Toxicological Concern


Acknowledgements

WRAP and Nextek Limited would like to thank Ian Cooper and his team of analysts at Smithers-Pira and Dr Anna Gergely and Dr Mitchell Cheeseman of Steptoe and Johnson LLC (Brussels) for their valuable contributions to this investigation. The complete analysis provided by Steptoe & Johnson LLP in this matter is set forth in Appendix 3 to this report. Descriptions of Appendix 3 in the text of the report are the responsibility of the report’s author. Readers of the report should refer to Appendix 3 for a full understanding of the analysis by Steptoe & Johnson LLP.


1.0 Introduction and scope of the project The specific objective of this work was to confirm whether the recycled PP (rPP) resins made by a new recycling process from post consumer food packaging decorated with “in-mould labels” and direct printing inks meet the EU regulations for food contact. This project builds on the previous WRAP projects; “Scoping study into food grade polypropylene recycling” conducted in 2010 by Axion Consulting and “Development of a Food Grade Recycling Process for Post Consumer Polypropylene” conducted by Nextek Ltd in 2011 and “Food grade decontamination trials of household PP waste” conducted by Nextek in 2012. These projects showed that by using a combination of the Gneuss MRS and OHL-type rotary vacuum decontamination systems as part of a recycling process for post consumer polypropylene (PP) food packaging that the two grades produced (clear and coloured rPP) were suited for a very wide range of food contact applications for aqueous, acidic and many fatty foods under severe heating conditions and prolonged storage at room, chilled and frozen temperatures. A UK patent application (No. 1103495) has been lodged on the process. A noticeable characteristic of the PP packaging used in the last study was that the majority of the packaging had been printed or utilised “in-mould labels” (IMLs) as a form of branding and decoration on the outside of the packaging where they are not required to be suitable for direct food contact. The chemical analysis involved the decontamination and migration work carried out in the previous project did not find any specific chemicals from IMLs or direct printing inks. However in order to clearly confirm whether rPP from packaging with IMLs and direct printing inks meet the EU regulations for food contact, a further investigation was conducted to check specifically for the presence of potentially problematic chemicals (such as photo-initiators and synergists) or their degradation products from IMLs and printing inks. The flakes of clear and coloured recycled PP were largely free of printing inks due to the abrasion and exposure to the washing chemicals at high temperatures however in both cases some residues were visible from either tenacious pressure sensitive labels, in-mould labels or direct print. It was difficult to estimate the level of removal of the print due to the wide variety of printed formats used in PP packaging, however it can be stated that the majority (>80%) of input material was highly likely to have at least one of the print formats since this was how the prior food use was determined during a manual sort. The presence of print in the rPP post consumer packaging being tested in this evaluation would be expected to be higher than packaging sorted automatically using other techniques (such as markers of some type) to separate prior food-use packaging from non-food use packaging. This means that this study could be considered more challenging than normal since unprinted food use containers would otherwise be included reducing the relative proportion of printed packaging. The appearance of the input materials are shown in Figure 1 and flakes with residual inks are shown in Figure 2.


Figure 1: Clear and coloured PP flake prior to processing

Figure 2: Clear and coloured PP flakes with residual print prior to processing


2.0 Project Methodology The key stages in this project were:

1. A review of the existing test results and other scientific information from the earlier investigations where work was conducted by Smithers-Pira to determine what specific compounds are most likely to be present and also to be of concern as additives in packaging used in direct food contact. These substances were most likely in the classes of photo-initiators and synergists that assist the printing process including materials such as Bezophenone, “Padmate O” (2-ethylhexyl 4-(dimethylamino) benzoate) and Phosphine oxides as some have been of scientific concern in the food safety of inks.

2. Using samples of the two 100% rPP resins made in the last project, i.e. coloured and clear rPP, further testing was conducted to evaluate the presence of any residual substances. The level of removal of printed surfaces was evaluated by comparing washed flake samples with examples of original packaging such as yellow fats containers. The rPP resin samples were solvent extracted and concentrated multiple times to increase the detection sensitivity before testing by both GC/MS (gas chromatography/ mass spectroscopy) and LC/MS (liquid chromatography/ mass spectroscopy) to detect the presence of trace residual chemicals that may have been present at very low levels in the previous studies but not quantified.

3. The identification of the substances present in the rPP resins allowed the analysis of the specific molecules to be conducted on a quantitative basis using the two techniques mentioned above (GC/MS and LC/MS). Compounds identified were checked on the Swiss list of permitted substances that can be used in inks (now widely used as the reference list for the EU), and the European Printing Ink Association’s (EUPIA) Exclusion List that lists the materials that should not be used in inks, as a helpful references in deciding the risks associated with any residual substances identified in this work.

4. All identified substances were referred to the EFSA and USFDA regulations as well as scientific literature to assess their status and allowable limits for direct food contact. The levels were compared with limit of detection (LOD) that is specified at 10 ppb in EC regulation 10/2011 to establish if the substances were to be of concern. In addition the concentrations of substances were used with the “Migratest Lite” model to predict the migration of these substances into food under worst-case conditions of food type and temperature together with chilled and ambient storage. The quantitative identification of the type and concentration of any residual molecules would allow the appropriate conclusions to be deduced on the potential risks associated with the recycling of post consumer PP packaging that has been made with print and labels.

5. The residues that had unknown toxicological properties were evaluated using the approach known as “Threshold of Toxicological Concern” (TTC) which evaluates the substances based on the chemical structural classes and their related carcinogenic and or toxic potential.

6. The results and conclusions of these investigations were reviewed by a leading chemical law attorney (Steptoe and Johnson LLC) who were asked to review any classifications of residual substances and to validate their toxicity and human exposure levels as well as to review the reports conclusions and recommendations on the TTC approach.


3.0 Identification of traces of printing residues in post consumer PP packaging 3.1 Identification of contaminants from previous use of printing inks and in-mould labels In order to detect any residual substances in the two grades of rPP (clear and coloured), Smithers-Pira firstly calibrated their analytical equipment with 23 compounds (full report in Appendix 1) that might be found from the prior use of printing inks so that definite identifications could be readily made. The two resins were extracted using two sequences of three days and five days at 60°C to ensure extraction was as complete as possible. The solutions were then analysed after removing most of the solvents. The substances identified in the two resins were reported to be very similar, however, for the clear rPP more oligomers were extracted. Table 1 below shows the substances positively identified in the extractions aside from the expected oligomers of PP and stabilisers. These results were not quantitative due to the need to initially calibrate the equipment with the molecules being analysed.

Table 1: Substances identified in rPP compounds by solvent extraction

Substance identified in rPP resins CAS Number

Acetophenone 98-86-2

Benzophenone 119-61-9

1-hydroxy-cyclohexyl phenyl ketone (Irgacure 184) 947-19-3

Ethyl-4-dimethylaminobenzoate 10287-53-3

2,2-dimethoxy-2-phenyl acetophenone 24650-42-8

Methyl-2-benzoylbenzoate 606-28-0

2-ethylhexyl-4-(dimethylamino)benzoate (Escalol 507) 21245-02-3

2-methyl-1[4-methylthio)phenyl]-2-morpholinopropan-1-one (Irgacure 907)

71868-10-5

2-isopropylthioxanthone (Quantacure itx) 5495-84-1

4-phenylbenzophenone 2128-93-0

Diethylene glycol dibenzoate (DEGBA) 120-55-8

2,4-diethyl-9H-thioxanthen-9-one 82799-44-8

4-(4-methylphenylthio)benzophenone (Quantacure BMS) 83846-85-9

The analysis identified twelve compounds used in UV cured inks and one substance (DEGBA) used in ink formulations. Significantly, none of these compounds are on the EuPIA exclusion list that identifies substances that should not be used in the formulation of printing inks based on health and safety concerns. 3.2 Threshold of Toxicological Concern (TTC) EU Regulations 10/2011 specifies the materials that can be used in unlimited and limited quantities by publishing an approved list that may define the SML for specific substances. For the many other substances used in industrial applications including substances used in printing inks and labels, it is helpful to understand the potential toxicity of substances for which no toxicity database exists. The threshold of toxicological concern (TTC) is a pragmatic risk assessment tool that is based on the principle of establishing a human exposure threshold value for all chemicals, below which there is a very low probability of an appreciable risk to human health (Kroes R & Institute, 2004).


The concept that there are levels of exposure that do not cause adverse effects is inherent in setting acceptable daily intakes (ADIs) for chemicals with known toxicological profiles. The TTC principle extends this concept by proposing that a minimum value can be identified for many chemicals, in the absence of a full toxicity database, based on their chemical structures and the known toxicity of chemicals which share similar structural characteristics. The establishment and application of widely accepted TTC values avoids unnecessary toxicity testing and safety evaluations when human intakes are below such a threshold. An Expert Group of the European branch of the International Life Sciences Institute, ILSI Europe, has examined the TTC principle for its wider applicability in food safety evaluation. The Expert Group examined metabolism and accumulation, structural alerts, endocrine disrupting chemicals and specific endpoints, such as neurotoxicity, teratogenicity, developmental toxicity, allergenicity and immunotoxicity, and determined whether such properties or endpoints had to be taken into consideration specifically in a step-wise approach. The Expert Group concluded that the TTC principle can be applied for low concentrations in food of chemicals that lack toxicity data, provided that there is a sound intake estimate. The TTC approach has been used by EFSA as a tool for providing scientific advice about possible human health risks from low level exposures of contaminants in food. Smithers-Pira also classified the substances according to their Cramer Class, which can be indicative of the potential toxicity of the substance based on its chemical structure. This allows any untested substances to be screened either for priority setting or for deciding whether exposure to a substance is so low that the probability of adverse health effects is low and that no further data are necessary. In the Cramer scheme, substances were classified into three categories based on their potential toxicity with Class I being lowest order of concern and Class III being the highest order of concern. The three categories are: Class I. Substances with simple chemical structures and for which efficient modes of metabolism exist, suggesting a low order of oral toxicity. Class II. Substances that possess structures that are less innocuous than Class I substances, but do not contain structural features suggestive of toxicity like those substances in Class III. Class III. Substances with chemical structures that permit no strong initial presumption of safety or may even suggest significant toxicity or have reactive functional groups. Munro and coworkers subsequently used the Cramer decision tree with the purpose of deriving human exposure levels (TTC values) for toxicity endpoints (other than carcinogenicity) based on toxicity studies on rodents and rabbits (Munro IC, 1996). This approach allowed a conservative calculation of TTC exposure values for each Cramer class. On the basis of various independent analyses, using different datasets and endpoints of concern, these threshold values have been found to be robust and protective for human health CITATION EFS11 \l 3081 (EFSA, 2011). Table 2 provides a summary of TTC categories and exposure levels by person, body weight in food.


Table 2: Summary of TTC categories and exposure levels by person, body weight and in food

Type of TTC value TTC value in μg/person per day

TTC value in μg/kg bw per day

TTC value μg/kg in food (adults)

With structural alert for genotoxicity

0.15 0.0025 0.15

Organophosphates and carbamates

18 0.3 18

Cramer Class II and III

90 1.5 90

Cramer Class I 1800 30 1800

3.3 TTC Classification of ink residues in rPP Smithers-Pira used the software package Toxtree v2.5.1 (available from EC Joint Research Committee) to designate the contaminants in the rPP to a specific Cramer class to understand their potential toxicity and to be able to define the safe exposure limits. The thirteen substances are also categorized with regard to the Swiss regulations since only benzophenone is the only chemical that is positively listed by the EU regulation 10/2011 as a substance permitted to be used in contact with food. It has a specific migration limit of 0.6 mg/kg of food simulant. Since the EU Regulation does not list the other 12 substances, it is helpful to refer to the Swiss regulations CITATION Swi05 \l 3081 (Swiss FDHA, 2005) that have evaluated the migration limits for the substances. Smithers-Pira have tabulated the substances (shown in Table 3 below and in the full report in Appendix 2) and noted the specific migration limits for each substance as well classifying them as Part A and Part B. This is a way of separating substances that have been evaluated and have had migration limits specified as either (Part A) those that should not be used unless no transfer of these substances to food or food simulants can be detected, or (Part B) that lists substances with a limit of detection no greater than 0.01 mg/kg or 10 ppb. Table 3 shows the classification of residues in the rPP resins by Swiss Regulation and Cramer Class.

Table 3: Classification of residues in rPP resins by Swiss Regulation and Cramer Class

Substance identification CAS No. Toxtree evaluation or Safety Limit in food

Acetophenone 98-86-2 Swiss Part B negative for carcinogenicity Cramer Class I

Benzophenone 119-61-9 0.6 mg/kg EU Regulation 10/2011

1-hydroxy-cyclohexyl phenyl ketone (Irgacure 184)

947-19-3 Swiss Part B negative for carcinogenicity Cramer Class II

Ethyl-4-dimethylaminobenzoate 10287-53-3 Swiss Part A 0.05 mg/kg (under Evaluation) Cramer Class III, structural alert for genotoxicity.

2,2-dimethoxy-2-phenyl acetophenone

24650-42-8 Swiss Part B negative for carcinogenicity Cramer Class III

Methyl-2-benzoylbenzoate 606-28-0 Swiss Part A 0.05 mg/kg (under Re-valuation) negative for carcinogenicity


Cramer Class III

2-ethylhexyl-4-(dimethylamino)benzoate (Escalol 507)

21245-02-3 Swiss Part A 5 mg/kg (under Re-valuation) Cramer Class III, structural alert for genotoxicity.

2-methyl-1[4-methylthio)phenyl]-2- morpholinopropan-1-one (Irgacure 907)


2-isopropylthioxanthone (Quantacure itx)

5495-84-1 Swiss Part A 0.05 mg/kg negative for carcinogenicity Cramer Class III

4-phenylbenzophenone 2128-93-0 Swiss Part B under re-evaluation negative for carcinogenicity Cramer Class III

Diethylene glycol dibenzoate (DEGBA)

120-55-8 Swiss Part B negative for carcinogenicity Cramer Class I

2,4-diethyl-9H-thioxanthen-9-one 82799-44-8 Swiss Part B negative for carcinogenicity Cramer Class III

4-(4-methylphenylthio)benzophenone (Quantacure BMS)


The four substances that are on the Swiss Part A list have detection limits as shown in Table 3 and the limits in migration tests range from 0.05 mg/kg to 5 mg/kg. The eight substances on Swiss Part B list must not be detectable in migration tests using valid methods of analysis but must not exceed the limit of detection of 0.01 mg/kg (10 ppb). There are four substances on the Swiss Part A list, two with structural alerts for genotoxicity and two negative for carcinogenicity. The Cramer classification of these substances is Class III that is of high concern with 20 times lower migration limits than Class I as shown in Table 2. There are eight substances on the Part B list with two Cramer Class I, one with Cramer Class II and five Cramer Class III substances. These classifications allowed the presence of substances to be judged as innocuous or of concern once the quantitative analysis provides the actual concentrations in the resins. From that data, the migration into food was estimated using migration modelling which provided clear guidance to the safety of these resins for direct food contact. 3.4 Quantitative analysis of contaminants in rPP resins

Smithers-PIRA undertook the quantitative analysis by extracting the resins with solvents for 4 days at 60 °C as well as preparing standard reference solutions of each substance to precisely calibrate the response GC/MS equipment to those substances to levels close to the limit of detection.

The average concentration of each substance was then used in the migration-modelling program “ Migratest Lite” to predict levels of migration into food using worst-case scenarios. For these calculations the substances were assumed to be freely soluble in the food (in this case the simulant olive oil) with test conditions of 10 days at 20°C, 40°C and 60°C. The thickness of the polymer was assumed to be 250 micron, which is a typical thickness for many food containers. The specific migration limit (SML) applied to each substance is also shown in Table 4 as well as in the full report in Appendix 2. The migration limit for substances on the Swiss Ordinance Part B list was set at 0.01 mg/kg or 10 ppb.


Table 4 shows the average concentration of residues in rPP and migration into food.

Table 4: Average concentration of residues in rPP and migration into food

Substance and SML

PP Sample 1 (Clear) PP Sample 2 (Coloured)

SML based on Swiss Ordinance Annex 6 or EU Reg 10/2011

Conc. in polymer (mg/kg)

Migration (mg/kg) T= 20°C



Conc. in polymer (mg/kg)




Acetophenone SML = 0.01 mg/kg

0.02

0.00020 0.00025 0.00025 0.07 0.00070 0.00085 0.00085

Benzophenone SML = 0.6 mg/kg

0.21

0.0016 0.0030 0.0030 0.16 0.0012 0.0022 0.0022

1-hydroxy-cyclohexyl phenyl ketone (Irgacure 184) SML = 0.01 mg/kg

0.07

0.00041 0.00085 0.00085 0.06 0.00035 0.00075 0.00075

Ethyl-4-dimethylamino benzoate SML =0.05 mg/kg

0.01

0.00007 0.00015 0.00015 0.02 0.00011 0.00023 0.00023

2,2-dimethoxy-2-phenyl acetophenone SML = 0.01 mg/kg

0.08

0.00040 0.0010 0.0011 0.06 0.00030 0.00075 0.00075

Methyl-2-benzoylbenzoate SML = 0.05 mg/kg

0.08

0.00040 0.0010 0.0015 0.05 0.00030 0.00060 0.00071

2-ethylhexyl-4-(dimethylamino) benzoate (Escalol 507) SML = 5 mg/kg

0.11

0.00045 0.0013 0.0014 0.11 0.00045 0.0013 0.0015

2-methyl-1[4-(methylthio)phenyl]-2-morpholinopropan -1-one (Irgacure 907) SML = 0.01 mg/kg

0.03

0.00012 0.00040 0.00040 0.11 0.00045 0.0014 0.0014

Isopropylthio xanthone (Quantacure itx) SML = 0.05 mg/kg

0.07

0.00033 0.0009 0.0009 0.20 0.0009 0.0025 0.0025

4-phenylbenzo phenone SML = 0.01 mg/kg

0.40

0.0018 0.0050 0.0055 0.61 0.0030 0.0080 0.0080

x x

x x

x x

x x

x x

x x

x x

x x

x x

x x


Diethylene glycol dibenzoate (DEGBA) SML = 0.01 mg/kg

0.05

0.00016 0.00053 0.00063 not

detected*

- - -

2,4-diethyl-9H-thioxanthen-9-one SML = 0.01 mg/kg

0.07

0.00030 0.00080 0.00085 0.13 0.00060 .0016 0.0017

4-(4-methylphenylthio) benzophenone (Quantacure BMS) SML = 0.01 mg/kg

0.02

0.00009 0.00030 0.00033 0.05 0.00018 0.00060 0.00065

It is readily noted that both resins had similar concentrations for nearly all of the residues and that many of the concentrations were less than 0.22 ppm (except for phenylbenzophenone) indicating that the analysis would be technically challenging. -Phenylbenzophenone was present at 0.6 ppm in the coloured rPP resin and 0.4 ppm in the clear resin.

The limit of detection for each substance was in each case estimated from visual inspection of the chromatograms and is shown in the Table 5. This is typically at 20 or 30 ppb and confirms that the substances are present at very low levels. Smithers-Pira did comment on the difficulty in the analysis for 2-ethylhexyl-4-(dimethylamino)benzoate (Escalol 507) due to reactions or absorption which would lead to less confidence in the results for that substance. The concentrations measured and predicted migration levels calculated are still well below (3000 times lower) the SML providing a large safety factor.

Table 5 shows the limit of detection for each substance.

Table 5: Limit of detection for each substance

Substance LOD (mg/kg)

Acetophenone 0.02

Benzophenone 0.02

1-hydroxy-cyclohexyl phenyl ketone (Irgacure 184)

0.02

Ethyl-4-dimethylaminobenzoate 0.02


0.02

Methyl-2-benzoylbenzoate 0.03

2-ethylhexyl-4-(dimethylamino)benzoate (Escalol 507)

0.02

2-methyl-1[4-methylthio)phenyl]-2- morpholinopropan-1-one (Irgacure 907)

0.02

Isopropylthioxanthone (Quantacure itx)

0.03

4-phenylbenzophenone 0.03

Diethylene glycol dibenzoate (DEGBA)

0.03

2,4-diethyl-9H-thioxanthen-9-one 0.03

x x

x x

x x


4-(4-methylphenylthio)benzophenone (Quantacure BMS)

0.02

3.5 Migration simulation

The results of the migration modelling for 20°C, 40°C and 60°C shows that in all thirteen substances the quantity predicted to migrate to food was less than the specific migration limit (SML) for each substance. The results are typically 10 to 100 times less than the SML even at the worst case of 60°C into olive oil food simulant. The only result that was close to the limit was for the most abundant substance, 4-phenylbenzophenone, which was less than the SML by 20% at 8 ppb compared to the limit of 10 ppb.

The relationship between the concentration present in the resin and the migration into food is depicted in Figures 3 and 4.

Figure 3: Concentration and migration of residues in clear PP.

Figure 4: Concentration and migration of ink residues in coloured rPP


The two figures reinforce the similarities in the residues found in two resins, the relatively high level of 4-phenylbenzophenone and the very low level of migration into the food simulant at the highest temperature of 60°C. Smithers-Pira based the estimations of migration to food on a 250 micron monolayer of polypropylene and test conditions representing storage 10 days at 20°C covering chilled and frozen storage, 10 days at 40°C covering ambient storage up to 30 days and 10 days at 60°C covering ambient storage over 6 months. It was assumed that the substances were very soluble in the food simulant that was chosen as olive oil and the packaging area food volume ratio was assumed to be the conventional EU packaging ratio of 6dm2/kg. All of the estimated migration values were less than the limits assigned to each substance based on their respective SML values. The test conditions of 10 days at 60°C represents total mass transfer for these substances from the resin into the food simulant. Therefore, it can be concluded that as long as the food packaging is less than 250 microns, the migration of these substances will not exceed 0.01 mg/kg. 3.6 Conclusions based on the migration data on food safety of the rPP resins Based on the concentrations measured by Smithers-Pira in the two resins and the subsequent predictions of the concentrations that would migrate under the most severe conditions of temperature and food type (60°C and olive oil) it can be stated that the resins would represent negligible risk based on the specific migration limits recommended by the Swiss Ordinance. The concept of “mutual recognition” concerning the control of non-harmonised substances means that the regulations developed in Switzerland (which has special status as a non-member of the EU) can be applied in other States with the assumption that there is adequate protection of public health. On this basis, the two resins could be used in direct food contact applications with the confidence that the residues from ink and labels remaining in the rPP would not migrate into food at levels exceeding those recommended.


4.0 Review of compliance with US FDA and EFSA regulations

The legal firm, Steptoe and Johnson examined the technical results in order to thoroughly review the data and the legal standing of any conclusions of compliance to EU and US regulations and suitability of the resins for direct food contact on the basis of the presence of the identified ink residues. Dr Anna Gergely and Dr Mitchell Cheeseman conducted the review and the full report is in Appendix 3. The highlights of their key observations and conclusions are presented below. However, please note that this summary should not be relied upon in isolation. Readers are specifically directed to read the full review (within Appendix 3)

4.1 Legal attorney review of the analytical results Steptoe and Johnson reported that the two resins complied with EU Framework regulation 1935 /2004 Article 3, which ensures that packaging does not endanger health and does not unacceptably change the composition and taste of food, and EU Regulation 10/2011 that allows for the demonstration of the safety of non-intentionally added substances (NIAS) that are not on the EU list of positive materials by migration testing. Similarly they stated that the resins would comply with the USFDA regulation 21 CFR 174.5 “Requirements for recycled plastics used in food contact applications” since it could be demonstrated that the residues would not migrate at levels that would create dietary intakes that would exceed those recommended to represent negligible risk. In summary Steptoe and Johnson stated “Based on the information that you provided to us we can advise you that the remaining traces of thirteen impurities from printing inks as quantitatively measured and reported by Smithers Pira in the two samples of recycled polypropylene resins meet the regulatory requirements in the EU and the US for direct food contact application on the basis of their reported concentrations, toxicity and estimated exposure levels. Specifically, comparing the worst case migration data derived from the Migratest Lite model on the basis of residual levels of these impurities established by Smithers Pira with the maximum permitted migration values showed compliance with the safety limits established by Article 3 of the Framework Regulation for these substances.

Similarly, based on the TTC approach using estimated daily intakes assumed for food contact polypropylene in the U.S. containing the thirteen impurities, two of the migrants contained structural alerts related to potential mutagenicity. Their estimated daily intakes were comfortably below the TTC level ordinarily applied to substances with non-potent mutagenic alerts and so their migration represents no more than negligible risk. Therefore, the potential risk from migration of these substances from food contact polypropylene can be considered negligible and the two recycled polypropylene batches can be considered of suitable purity for their intended use under 21 CFR 174.5, with respect to these thirteen migrants.”

In reaching this position Steptoe and Johnson thoroughly reviewed the analytical procedure and due to the lower than usually accepted “recovery values” for some of the analyses (which reflect the precision of the procedure), made conservative adjustments to the migration results by assuming the actual migration was double of that predicted by Smithers-Pira. They also applied the stringent criteria of dietary exposure for Cramer class II and III substances of 1.5 µg/p/d to the 13 substances with the exception of benzophenone that is on the EU positive list and has a SML of 0.6 mg/kg. They also assumed that a person ate 3 kilograms of food per day packaged in PP with all 13 of the residues.


The classification of the thirteen substances and the calculation of the estimated dietary intake (EDI) is shown in Table 6.

Table 6: Migration and Estimated Dietary Intake (EDI) results for clear (Sample 1) and (Sample 2) coloured rPP (Steptoe and Johnson)

Substances identified in rPP as residues of

printing inks

Cramer Class

Migration Sample 1

(ppb)

EDI Sample1 µg/p/d

Migration Sample2

(ppb)

EDI Sample2 µg/p/d

Acetophenone I 0.25 0.03 0.85 0.01

Benzophenone N/A 3.00 0.36 2.20 0.26

1-hydroxy-cyclohexyl phenyl ketone

II 0.85 0.1 0.75 0.09

Ethyl-4-dimethylaminobenzoate

III* 0.15 0.02 0.23 0.03


III 1.10 0.13 0.75 0.09

Methyl-2-benzoylbenzoate III 1.50 0.36 0.71 0.09

2-ethylhexyl-4-(dimethylamino)benzoate

III* 1.40 0.34 1.50 0.36

2-methyl-1[4-methylthio-phenyl]-2-morpholinopropan-1-one

III 0.40 0.05 1.40 0.17

Isopropylthioxanthone III 0.07 0.016 0.20 0.04

4-phenylbenzophenone III 5.50 1.32 8.00 0.96

Diethylene glycol dibenzoate

III 0.63 0.05 -

2,4-diethyl-9H-thioxanthen-9-one

III 0.85 0.20 1.70 0.2

4-(4-methylphenylthio) benzophenone

III 0.33 0.08 0.65 .08

* Compounds observed to have a structural alert for mutagenicity

Steptoe and Johnson also note that two of the substances have a structural alert for mutagenicity (based on the substance having a structure similar to substances that are known to be mutagenic) and the TTC level applied to these substances is 0.15 µg/p/d and while one (Ethyl-4-dimethylaminobenzoate) is well below this level the other (2-ethylhexyl-4-(dimethylamino)benzoate) is approximately twice this level. They state that the conservative nature of the exposure assessment and the relative potency of structurally similar compounds indicate that migration of this substance is no more than negligible risk. Overall they endorsed that the two batches of rPP can be considered of suitable purity for use as food packaging under the EU regulations and USFDA regulations.


5.0 Conclusions The investigations conducted on the two grades of clear and coloured rPP resins produced by the specific recycling process described in UK patent application (No. 1103495) related to this project have shown that:

1. Most of the inks present on PP packaging as direct print and IMLs have been removed during the washing process through the application of the abrasion and chemicals used in the washing process;

2. Thirteen residues from the printing inks and IMLs have been detected in both resins; 3. The residues are present in very low concentrations and are not likely to migrate to

food, even under extreme temperature and food type, in concentrations that will endanger human health;

4. The two resins are compliant for food use according to the regulations used in the EU as well as USA; and

5. The TTC approach provides useful guidelines for the classification of substances that have not been fully studied with regard to their specific toxicology.

6. These results confirm that the rPP with in-mould labels and direct printing inks that has been decontaminated with the process described in the specific recycling process described in UK patent application (No. 1103495), is suitable for direct food contact use in conditions representing storage for 10 days at 60°C covering ambient storage over 6 months as well as chilled and frozen storage. These comments are specifically directed to the migration of substances used in in-mould labels and printing inks and should be considered along with earlier recommendations relating to the limits on food types and storage conditions for the two types of rPP which showed (amongst other acceptable conditions) that the rPP resins could be used with many fatty foods for 10 days at 40°C as well as other specific food types (aqueous and acidic) and other temperature conditions up to 121°C. .

7. The results should provide confidence to the packaging and recycling industry to continue to develop and commercialise a food grade recycling process for post consumer PP packaging and has provided a methodology to continually measure/test/monitor the presence of substances of concern that could be used throughout the commercialisation/development process.


6.0 Recommendations This investigation utilised resins produced as part of a large scale PP recycling trial and sourced many types of PP food packaging with a wide range of decoration systems such as direct print, IMLs and pressure sensitive labels in paper and plastic. It is not known how widely the printing systems and their ingredients might vary in different parts of UK, Europe and the rest of the world and it would be advisable to recheck the validity of the conclusions of this investigation with other sources of PP put through the same recycling process at least within Europe to be confident that the same outcome is achieved. This should be done during the development of any full-scale commercial processes. One substance extracted from the rPP was measured at the significantly higher levels than any of the other ink residues; 4-phenylbenzophenone. It is not understood why this was the case however it would be useful if food safety and industry bodies investigated why this component was present in relatively large concentrations to understand under what conditions the levels could go even higher and exceed the migration limits. The printing industry is also changing its formulations as it is challenged by new regulations for worker health and safety and it would be appropriate for these changes to be monitored so that any implications of eliminating some components and introducing new substances are understood. This can be readily achieved by close liaison between food safety bodies and an industry association such as EUPIA. The commercialisation of the specific recycling process or others of similar or better decontamination efficiency can proceed with the knowledge that there are negligible risks of contamination from the presence of printed labels and direct printing. The remaining technical issue will be the need to develop techniques that can separate prior-food-use packaging from non-food use packaging.


7.0 Bibliography EFSA. (2011). Report of ESCO WG on non-plastic Food Contact Materials1 (Vol. EN139). EFSA. EFSA. (2012) Scientific Opinion on Exploring options for providing advice about possible human health risks based on the concept of Threshold of Toxicological Concern (TTC) Kroes R, R. A., & Institute, E. b. (2004). Structure-based thresholds of toxicological concern (TTC): guidance for application to substances present at low levels in the diet. (Vol. 42). Journal of Food and Chemical Toxicology. Munro IC, F. R. (1996). Correlation of structural class with no-observedeffect levels: a proposal for establishing a threshold of concern (Vol. 34). Food and Chemical Toxicology. Swiss FDHA. (2005). Ordinance of the FDHA on articles and materials (RS 817.023.21) of 23 November 2005.


Appendix 1. Analysis of residues in rPP

(Smithers-PIRA)









Appendix 2. Quantitative analysis of

contaminants in rPP from printing inks

(Smithers-Pira)
















Appendix 3. Report on rPP for direct food

contact – Steptoe and Johnson LLP













www.wrap.org.uk/plastics

Documents

Final Report Further analysis of decontaminated recycled ... analysis of decon rPP.pdf · Further analysis of decontaminated recycled polypropylene (rPP) 1 Executive summary Introduction